Neisseria meningitidis NadA is a new invasin which promotes bacterial adhesion to and penetration into human epithelial cells

Speaker︰    伍展弘                  Time: 13:00-14:00 2005/03/09

Commentator: 何漣漪  老師            Place: Room 601

Abstract:

Neisseria meningitidis, a major cause of human septicemia and meningitis, is facultative commensals because they were colonized onto the nasopharynx of 3–30% of healthy individuals. It could traverse the mucosal barrier and enter into bloodstream to cause septicemia, and also traverse the blood-brain barrier to result in fulminant meningitis (1). The first step of pathogenesis is colonized onto the respiratory epithelium, followed by invasion into the cell, intracellular persistence and transcytosis. These events are modulated by the interaction of virulence factors with their host cell receptors. NadA (Neisseria adhesin A) is a novel surface antigen for a vaccine which is able to control meningococcal disease and present in many known hypervirulent lineages. NadA is surface-exposed oligomeric protein, which binds to host cells in vitro suggesting that it could belong to a novel class of adhesins (2). In this study, NadA was expressed by the pET system in Escherichia coli and assembled in oligomers anchored to the outer membrane. The result showed that NadA can promote E. coli adhesion and invasion into Chang epithelial cells. These effects were disappeared when the N-terminal globular domain of NadA was deletion or pretreating pronase of Chang cells. By inactivation of the nadA gene, the ability of adhesion and invasion of N. meningitidis was reduced when comparing to the wild type strain. These data suggested that NadA increases the capabilities of hypervirulent Neisseria meningitidis in adhesion and invasion (3).

Reference:

1.      Merz, A.J., and So, M. (2000) Interactions of pathogenic Neisseriae with epithelial cell membranes. Annu Rev Cell Dev Biol 16: 423–457.

2.      Comanducci, M., Bambini, S., Brunelli, B., Adu-Bobie, J., Arico’, B., Capecchi, B., et al. (2002) NadA, a novel vaccine candidate of Neisseria meningitidis. J Exp Med 195: 1445–1454.

3.      Barbara, C., Jeannette A.B., et al. (2005) Neisseria meningitidis NadA is a new invasin which promotes bacterial adhesion to and penetration into human epithelial cells. Molecular Microbiology 55: 687-698.